Valve device

ABSTRACT

A valve device includes: a ball valve having a ball face shaped in a convex spherical surface; and a valve seat having a seat face shaped in a concave spherical surface. The seat face is pressed onto the ball face. The ball valve is rotated to open a valve by communicating a valve opening defined in the ball valve and a seat opening defined in the valve seat with each other, and to close the valve by stop the communication. A diameter of the seat opening ϕ 2  is smaller than a diameter of the valve opening ϕ 1 . A curvature radius of the ball face R 1  is smaller than or equal to a curvature radius of the seat face is R 2.

CROSS REFERENCE TO RELATED APPLICATION

This application is a continuation application of application Ser. No.15/121,201, filed Aug. 24, 2016 which is the U.S. national phase ofInternational Application No. PCT/JP2015/003131 filed Jun. 23, 2015,which designated the U.S. and claims priority to Japanese PatentApplication No. 2014-139702 filed on Jul. 7, 2014, Japanese PatentApplication No. 2014-139729 filed on Jul. 7, 2014, Japanese PatentApplication No. 2014-139759 filed on Jul. 7, 2014, Japanese PatentApplication No. 2014-139789 filed on Jul. 7, 2014, Japanese PatentApplication No. 2014-181346 filed on Sep. 5, 2014, and Japanese PatentApplication No. 2015-86608 filed on Apr. 21, 2015, the entire contentsof each of which are hereby incorporated herein by reference.

TECHNICAL FIELD

The present disclosure relates to a valve device in which a concavespherical valve seat is pressed onto a convex spherical ball face, andfor example, a technique suitably used for a valve device that controlscooling water as an example of fluid. The convex spherical face refersto a spherical shape protruding outward, and the concave spherical facerefers to a spherical shape recessed inward.

BACKGROUND ART

In a conventional valve device, a concave spherical seat face of a valveseat is pressed onto a convex spherical ball face of a ball valve torotate the ball valve, thereby switching communication andnon-communication between a valve opening of the ball valve and a seatopening of the valve seat (see, for example, Patent Literature 1).

In the conventional valve device, a diameter of the seat opening matchesa diameter of the valve opening. Alternatively, the diameter of the seatopening is larger than the diameter of the valve opening. The diameterof the opening is an inner diameter of each opening.

The seat face of the valve seat is pressed onto the ball face of theball valve. The ball valve rotates at opening/closing and adjustment ofthe degree of opening. Thus, the ball face and the seat face slide incontact with each other under pressure.

Here, the ball face of the ball valve moves with respect to the seatface. For this reason, a site of the ball face in contact with the seatface at opening is different from a site of the ball face in contactwith the seat face at closing. On the contrary, since the seat face doesnot move, the site of the seat face in contact with the ball face atopening is the same as the site of the seat face in contact with theball face at closing.

That is, at closing of the valve, the ball face contacts the seat faceonly at closing, while the seat face contacts the ball face continuouslyfrom closing to full opening. Thus, the site of the ball face in contactwith the seat face at closing is hard to wear.

On the contrary, the site of the seat face in contact with the ball faceat closing slides on the ball face at all times and thus, is susceptibleto wear. For this reason, when the valve device is used for a long time,the seat face that ensures a sealing property at closing wears earlierthan the ball face that ensures the sealing property at closing,possibly causing leakage at closing.

The valve seat in Patent Literature 1 is assembled to a holding memberusing a cylindrical portion attached to the periphery of the valve seat.Since the cylindrical portion in Patent Literature 1 is an individualcomponent for attaching the valve seat to the holding member, the numberof components increases.

Further, since the cylindrical portion in Patent Literature 1 forms anannular groove receiving the valve seat, the axial length of thecylindrical portion is larger than the thickness of the valve seat. Asdescribed above, in the valve device having the conventionalconfiguration, the valve seat is susceptible to wear. For this reason,when the valve seat continues to wear and becomes thinner, the ballvalve may directly contacts the cylindrical portion, eliminating thesealing effect of the valve seat.

PRIOR ART LITERATURES Patent Literature

-   -   Patent Literature 1: JP 2008-232260 A

SUMMARY OF INVENTION

An object of the present disclosure is to provide a valve device capableof restricting deterioration in the sealing property due to slidingwear.

According to an aspect of the present disclosure, a valve deviceincludes: a ball valve having a ball face shaped in a convex sphericalsurface; and a valve seat having a seat face shaped in a concavespherical surface. The seat face is pressed onto the ball face. The ballvalve is rotated to open a valve by communicating a valve openingdefined in the ball valve and a seat opening defined in the valve seatwith each other. A diameter of the seat opening is smaller than adiameter of the valve opening, and a curvature radius of the ball faceis smaller than or equal to a curvature radius of the seat face. Thatis, a following relationship is satisfied: ϕ1>ϕ2; and R1≤R2.

Thus, the site of the seat face in contact with the ball face at openingis different from the site of the seat face in contact with the ballface at closing. That is, the site of the seat face in contact with theball face at closing to ensure the sealing property can be provided soas not to contact the ball face at opening. For this reason, wear of thesite of the seat face in contact with the ball face at closing to ensurethe sealing property can be reduced, ensuring the sealing property atclosing for a long time.

BRIEF DESCRIPTION OF DRAWINGS

The above and other objects, features, and advantages of the presentdisclosure will be more apparent from following description withreference to appended figures.

FIG. 1 is a sectional view illustrating a valve device at opening (afirst embodiment).

FIG. 2 is a sectional view illustrating the valve device at closing (thefirst embodiment).

FIG. 3 is a view illustrating a contact site of a ball face and a seatface (the first embodiment).

FIG. 4 is a sectional view illustrating a valve device at opening (asecond embodiment).

FIG. 5 is a sectional view illustrating a valve device at closing (athird embodiment).

FIG. 6 is a sectional view illustrating a valve device taken along anaxial direction (a fourth embodiment).

FIG. 7 is a view illustrating the valve device when viewed in an axialdirection (the fourth embodiment).

FIG. 8 is a schematic view illustrating an engine cooler (a fifthembodiment).

FIG. 9 is a sectional view illustrating a valve device (the fifthembodiment).

FIG. 10 is a partial enlarged view of FIG. 9 (the fifth embodiment).

FIG. 11 is a sectional view taken along XI-XI in FIG. 10 (the fifthembodiment).

FIG. 12 is a sectional view illustrating a valve device (a modificationof the fifth embodiment).

FIG. 13 is a sectional view illustrating a valve device (a modificationof the fifth embodiment).

DESCRIPTION OF EMBODIMENTS

Embodiments are specific examples, and as a matter of course, thepresent disclosure is not limited to the embodiments.

First Embodiment

As illustrated in FIG. 1 to FIG. 3, a valve device is mounted in avehicle, and a seat face 2 a of a valve seat 2 is pressed onto a ballface 1 a of a ball valve 1 to rotate the ball valve 1, therebycontrolling a flow rate or distribution of engine cooling water.

The valve device includes:

-   -   a housing 3 having an inlet through which cooling water is        guided from an engine, and an outlet through which the cooling        water is discharged, the cooling water being controlled in        amount in the valve device;    -   a shaft rotatably supported with respect to the housing 3;    -   an electrical actuator that rotates the shaft;    -   a ball valve 1 that rotates integrally with the shaft; and    -   a ring-shaped valve seat 2 pressed onto the ball valve 1.

Specifically, the ball valve 1 has a valve opening 1 b penetratingthrough the ball valve, and the valve seat 2 has a seat opening 2 bpenetrating the center of the valve seat 2. The ball valve 1 is rotatedso as to communicate the valve opening 1 b with the seat opening 2 b tobe opened, and so as not to communicate the valve opening 1 b with theseat opening 2 b to be closed.

As illustrated in FIG. 3, the valve opening 1 b in the embodiment is anellipse hole extending along the rotating direction of the ball valve 1.Specifically, the valve opening 1 b is an ellipse hole having an edgethat is parallel to the rotating direction of the ball valve 1.

The ball valve 1 is rotated by the electrical actuator via the shaft.For example, the ball valve 1 is substantially cup-shaped. Although theflow direction of cooling water is not limited, as an example forfurther understanding, cooling water supplied through the inlet is fedfrom a cup opening into the inside of the ball valve 1. When the ballvalve 1 is opened, the cooling water fed to the inside of the ball valve1 is guided to the outlet through an overlapping site of the valveopening 1 b and the seat opening 2 b.

The ball valve 1 is made of, for example, resin such as PPS, and thesmooth ball face 1 a having a convex spherical shape is in slide-contactwith at least the valve seat 2. That is, the ball valve 1 has the convexspherical ball face 1 a, and is rotated by the electrical actuator. Asshown in FIG. 6, an inner wall surface 1 h of the valve 1 is parallelwith a seat face of the valve 1.

The valve seat 2 is a ring body having the seat opening 2 b at itscenter, and is made of resin such as PTFE. The concave spherical seatface 2 a of the valve seat 2 is pressed onto the ball face 1 a of theball valve 1, and smoothly slides on the ball face 1 a.

The valve seat 2 is supported by the housing 3, and the housing 3 has asupport portion that supports the valve seat 2.

The support portion is configured of:

-   -   a spacer 5 fixed to a passage wall of the housing 3;    -   a spring 6 disposed between the valve seat 2 and the spacer 5;    -   a plate 7 disposed between the spring 6 and the spacer 5; and    -   a sleeve 8 that supports the valve seat 2.

The spacer 5 is fixed to, for example, an inner wall of the passageleading to the outlet by press-fitting, and is substantiallycylindrical. For example, the spring 6 is a compression coil spring, andis assembled in the compressed state. The plate 7 is a metal springwasher shaped like a ring-like circular plate.

The sleeve 8 is a substantially cylindrical passage member that supportsthe valve seat 2 at one end closer to the ball valve 1 and is insertedinto the spacer 5 at the other end farther from the ball valve 1, andserves to guide cooling water passing through the seat opening 2 b tothe outlet.

Specifically, the sleeve 8 is made of a metal material having a highcorrosion resistance, such as stainless steel, and at one end of thetubular sleeve 8, a tubular body 8 a that locks an outer end of thevalve seat 2 from the outer side in the radial direction, and a ringplate 8 b that is in press-contact with the opposite face of the seatare integrally provided as means for supporting the valve seat 2. Theseat opposite face is a face opposite to the seat face 2 a of the valveseat 2.

A more specific example will be described below. An outer end of thevalve seat 2 in the embodiment is a cylindrical face formed on the outercircumferential edge of the ring-like valve seat 2. The tubular body 8 alocks the outer end of the valve seat 2 to prevent extension of thevalve seat 2, and is shaped like a cylinder that is shorter in the axialdirection than in the radial direction. The cylindrical face at theouter end of the valve seat 2 is pressed into the inner circumferentialface of the tubular body 8 a by press-fitting, to prevent the tubularbody 8 a from expanding in the radially outer direction of the valveseat 2.

The seat opposite face of the valve seat 2 is a ring-like plane, and thering plate 8 b is provided on the ring-like plane. Specifically, thering plate 8 b extends from the sleeve 8 inserted on the inner side ofthe spring 6 in a stepped manner outward in the radial direction. Theinner circumferential face of the tubular body 8 a locks the cylindricalface at the outer end of the valve seat 2, keeping the press-contact ofthe seat opposite face with the ring plate 8 b. Keeping thepress-contact of the seat opposite face with the ring plate 8 b preventsdeformation such as warp of the valve seat 2.

A seal member 9 such as a lip seal is disposed between the sleeve 8 andthe spacer 5, and a seal member 10 such as an O ring is disposed betweenthe housing 3 and the spacer 5.

In the valve device, the site of the seat face 2 a in contact with theball face 1 a at opening is different from the site of the seat face 2 ain contact with the ball face 1 a at closing. The configuration will bespecifically described below.

In the valve device, to differentiate the site of the seat face 2 a incontact with the ball face 1 a at opening from the site of the seat face2 a in contact with the ball face 1 a at closing, the site of the seatface 2 a, which is not in contact with the ball face 1 a at opening, isprovided on the inner side of the seat face 2 a.

Specifically, the seat face 2 a in the embodiment has a site that slideson the opening edge of the valve opening 1 b in parallel with the site,on the radially outer side of the seat opening 2 b. After a long-termuse, the sliding site generates a step D due to wear.

As a specific means, a diameter ϕ2 of the seat opening 2 b is madesmaller than a diameter ϕ1 of the valve opening 1 b. That is, given thatthe diameter of the valve opening 1 b is ϕ1, and that the diameter ofthe seat opening 2 b is 02, the valve device in the embodiment isprovided so as to satisfy the relationship ϕ1>ϕ2.

Here, as described above, the valve opening 1 b in the embodiment is anellipse hole extending in the rotating direction of the ball valve 1,and has an opening edge extending in parallel in the rotating direction.Thus, as illustrated in FIG. 3, the diameter ϕ1 of the valve opening 1 bis determined depending on the width of the ball valve 1 in the rotationaxial direction.

In the valve device in the embodiment, to differentiate the site of theseat face 2 a in contact with the ball face 1 a at opening from the siteof the seat face 2 a in contact with the ball face 1 a at closing, thesite of the seat face 2 a, which is not in contact with the ball face 1a at opening, needs to be provided so as to contact the ball face 1 a toensure the sealing property at closing. Specifically, the radially innerside of the seat face 2 a needs to reliably contact the ball face 1 a atclosing.

Thus, a curvature radius R1 of the ball face 1 a is equal to or smallerthan a curvature radius R2 of the seat face 2 a. That is, given that thecurvature radius of the ball face 1 a is R1 and that the curvatureradius of the seat face 2 a is R2, the valve device in the embodiment isprovided so as to satisfy the relationship R1≤R2.

As a specific example, in the embodiment, a contact ring A that contactsthe ball face 1 a only at closing is provided at an end of the seat face2 a on the radially inner side. The contact ring A is a seal ring formedusing a curvature difference between the convex spherical ball face 1 aand the concave spherical seat face 2 a.

Specifically, as mentioned above, the ball face 1 a is a convexspherical face, and the seat face 2 a is a concave spherical face. Inthe embodiment, the curvature radius R1 of the ball face 1 a is set tobe smaller than the curvature radius R2 of the seat face 2 a.

In this manner, using the curvature difference between the ball face 1 aand the seat face 2 a, the contact ring A that contacts the ball face 1a at closing may be provided at only the end of the seat face 2 a on theradially inner side.

In the valve device in the embodiment, the site of the seat face 2 a incontact with the ball face 1 a at opening is different from the site ofthe seat face 2 a in contact with the ball face 1 a at closing. That is,the site of the seat face 2 a in contact with the ball face 1 a atclosing to ensure the sealing property does not contact the ball face 1a at opening.

Thus, wear of the site of the seat face 2 a in contact with the ballface 1 a at closing to ensure the sealing property can be suppressed fora long time, ensuring the sealing property at closing for a long time.Thus, long-term reliability of the valve device can be increased.

As described above, the valve opening 1 b in the embodiment is anellipse hole along the rotating direction of the ball valve 1. For thisreason, when the ball valve 1 is rotated, the edge of the ellipse holelocally contacts a portion of the seat face 2 a, generating the localstep D in the seat face 2 a due to wear.

However, even when the step D occurs in the seat face 2 a, since thesite of the step D is located on the radially outer side of the contactring A that ensures the sealing property at closing, the step D does noteffect on the sealing property at closing.

As described above, in the embodiment, even when the step D occurs inthe seat face 2 a, the edge of the ellipse hole forming the valveopening 1 b can ensure the sealing property at closing for a long time.

As described above, the valve device in the embodiment is provided withthe contact ring A that contacts the ball face 1 a only at closing, onthe radially inner end of the seat face 2 a.

The contact ring A can suppress wear caused by sliding as describedabove, and can control the contact width between the ball face 1 a andthe seat face 2 a by using the curvature difference between the ballface 1 a and the seat face 2 a. Accordingly, a load of the spring 6 canbe focused on the contact ring A, improving the sealing property betweenthe ball face 1 a and the seat face 2 a.

Even when the contact width of the contact ring A slightly increases dueto wear after long-term use, the site of the seat face 2 a in contactwith the ball face 1 a at closing can be limited on the radially innerside of the seat face 2 a ensuring the sealing property at closing.

Second Embodiment

A second embodiment will be described below with reference to FIG. 4.

Each of following embodiments adopt the mode in the first embodiment,and only differences between the embodiments and the first embodimentwill be described below. The elements having the same function infollowing embodiments as the element in the first embodiment are giventhe same reference numerals.

The valve device includes a rigid body that prevents deformation of thevalve seat 2. The rigid body locks at least the outer end of the valveseat 2 to prevent the valve seat 2 from extending in the radially outerside, and is provided integrally with the sleeve 8. Specifically, thesleeve 8 including the rigid body is made of metal such as stainlesssteel, and is provided by press working, trimming, or the like.

Here, the rigid body locks both of the cylindrical face at the outer endof the valve seat 2 and the seat opposite face. Specifically, the seatopposite face of the valve seat 2 is provided on the flat ring face, andthe rigid body is configured of the tubular body 8 a that covers thecylindrical face on the outer circumference of the valve seat 2, and theflat ring plate 8 b that is in press-contact with the whole seatopposite face that is a flat face. The specific example of the tubularbody 8 a and the ring plate 8 b is described in the first embodiment,detailed description thereof is omitted.

As described above, the rigid body locks the valve seat 2, and the valveseat 2 is fixed to the rigid body. The technique of coupling the valveseat 2 to the rigid body is not specifically limited, and press-fittingis adopted as an example.

As described above, in the valve device, the tubular body 8 a locks atleast cylindrical face on the outer end of the valve seat 2. Thus, evenwhen the valve seat 2 is made of resin or the like, the radially outerside of the seat face 2 a is prevented from extending outward due to theeffect of the ball face 1 a. That is, the valve seat 2 can be preventedfrom extending outward, avoiding leakage caused by deformation of thevalve seat 2 for a long time.

As described above, in the valve device, the tubular body 8 a locks atleast cylindrical face on the outer end of the valve seat 2, suppressingdeformation of the valve seat 2. For this reason, even when the valveopening 1 b of the ball valve 1 is an ellipse hole, the valve seat 2 isnot deformed into elliptical shape, preventing leakage caused bydeformation of the valve seat 2.

In the valve device, the curvature radius of the ball face 1 a is set tobe smaller than the curvature radius of the seat face 2 a. Then, thecontact site between the seat face 2 a and the ball face 1 a becomesextremely local, possibly causing deformation such as warp of the valveseat 2 due to the local stress concentration.

However, the rigid body in the second embodiment locks the cylindricalface on the outer end of the valve seat 2 as well as the seat oppositeface. Specifically, the tubular body 8 a locks at least cylindrical faceon the outer end of the valve seat 2, in the state where the seatopposite face is in press-contact with the ring plate 8 b. For thisreason, even when the contact site between the seat face 2 a and theball face 1 a becomes extremely local, deformation such as warp of thevalve seat 2 can be prevented, avoiding leakage caused by deformation ofthe valve seat 2 for a long time.

In the valve device, both of the ball face 1 a and the seat face 2 a aresmooth, and the friction coefficient μ1 between the ring plate 8 b andthe valve seat 2 in the rigid body is larger than the frictioncoefficient μ2 between the ball valve 1 and the valve seat 2.

Accordingly, at rotation of the ball valve 1, the ball valve 1 canreliably slide on the valve seat 2 at the contact site, suppressingslippage of the valve seat 2 with respect to the ring plate 8 b.

The tubular body 8 a is integrally formed with the ring plate 8 b. Thus,even when the tubular body 8 a is relatively thin, the ring plate 8 bacts to prevent deformation of the tubular body 8 a. Thus, for example,even when the tubular body 8 a is thin and thus, the tubular body 8 aalone lacks in strength, the ring plate 8 b can further preventdeformation of the tubular body 8 a.

That is, even when the rigid body is relatively thin, combination of thetubular body 8 a and the ring plate 8 b can effectively prevent thedeformation of the valve seat 2.

Patent Literature 1 discloses a cylindrical portion that covers thevalve seat 2. The cylindrical portion in Patent Literature 1 is anindividual component for assembling the valve seat 2 to the holdingmember, increasing the number of components.

On the contrary, the tubular body 8 a in the valve device in theembodiment is provided integrally with the sleeve 8 that serves as aguide for the spring 6. Specifically, the sleeve 8 in the embodimentintegrally has the portion inserted in the inner side of the spring 6 toguide the spring 6, the tubular body 8 a that guides the valve seat 2,and the ring plate 8 b that supports the valve seat 2. This can reducethe number of components of the valve device, and improve assembling ofthe valve device because of the reduction in the number of thecomponents.

The cylindrical portion disclosed in Patent Literature 1 is a componentforming an annular groove that receives the valve seat 2 and thus, thelength of the cylindrical portion in the axial direction is formed to belonger than the thickness of the valve seat 2. Thus, when the valve seat2 wears due to sliding of the ball valve 1, the ball valve 1 may contactthe cylindrical portion, eliminating the sealing effect of the valveseat 2.

On the contrary, according to the present embodiment, the length of thetubular body 8 a provided at the end of the sleeve 8 in the axialdirection is formed to be smaller than the thickness of the outercircumferential edge of the valve seat 2. That is, a portion of theouter circumferential edge of the valve seat 2 protrudes from thetubular body 8 a toward the ball valve 1.

Thus, even when the valve seat 2 wears due to sliding of the ball valve1, the ball valve 1 can be prevented from contacting the sleeve 8 toimprove long-term reliability of the valve device.

The above-mentioned advantage will be described more specifically.

As described in the first embodiment, the valve device in the secondembodiment satisfies relationship ϕ1>ϕ2 and R1 R2. As a specificexample, the valve device is provided so as to satisfy relationshipϕ1>ϕ2 and R1<R2.

For this reason, as described in the advantage 1 in the firstembodiment, the site of the seat face 2 a in contact with the ball face1 a at opening is different from the site of the seat face 2 a incontact with the ball face 1 a at closing, preventing wear of the valveseat 2 for a long time.

In addition to the advantage, in the second embodiment, by setting theaxial length of the tubular body 8 a to be smaller than the thickness ofthe outer circumferential edge of the valve seat 2, a portion of theouter circumferential edge of the valve seat 2 protrudes from thetubular body 8 a toward the ball valve 1.

For this reason, even when the valve seat 2 that suppresses wear becauseof the advantage of the first embodiment wears after long-term use, thetubular body 8 a can be formed to be short, preventing the ball valve 1from contacting the sleeve 8 to ensure long-term reliability of thevalve device.

Third Embodiment

A third embodiment will be described below with reference to FIG. 5. Atclosing, the valve device intentionally guides water pressure to both ofthe seat face 2 a and the seat opposite face of the valve seat 2. Theconfiguration will be specifically described below. A back pressurespace α in which cooling water flows from the inlet to the inside of thevalve device is formed on the side of the seat opposite face.

Specifically, the back pressure space α is a space around the sleeve 8at which the spring 6 is disposed. In more detail, the back pressurespace α is a space surrounded with the sleeve 8, the plate 7, the ringplate 8 b, and the passage wall of the housing 3 leading to the outlet.The back pressure space α communicates with the space that houses theball valve 1 in the housing 3 via a gap between the housing 3 and thering plate 8 b. The space that houses the ball valve 1 communicates withthe inlet at all times. Thus, as represented by a broken arrow X in thefigure, cooling water is guided from the engine into the back pressurespace α through the inlet.

Here, the ring plate 8 b provided at one end of the sleeve 8 extendsfrom the sleeve 8 to the radially outer side in a stepped manner. As aresult, the pressure of water guided to the back pressure space α isapplied to the face of the ring plate 8 b seated by the spring 6.

As a result, as the water pressure increases, the force to press thevalve seat 2 onto the ball valve 1 becomes larger.

The contact ring A that causes only the radially inner side of the seatface 2 a to contact the ball face 1 a is provided at the portion wherethe ball face 1 a is opposed to the seat face 2 a at closing.

Although the shape and the contact width of the contact ring A are notspecifically limited, a specific example of the contact ring A will bedescribed below. In the embodiment, the curvature radius of the ballface 1 a is smaller than the curvature radius of the seat face 2 a. Withthe configuration, the curvature difference between the ball face 1 aand the seat face 2 a forms the contact ring A that causes only the endof the seat face 2 a on the radially inner side to contact the ball face1 a at closing.

Providing the contact ring A forms an annular gap β, into which coolingwater flows, on the outer circumferential side of the contact ring A,and between the ball valve 1 and the valve seat 2 at closing. Theannular gap β communicates with a space that houses the ball valve 1 inthe housing 3 and leads to the inlet. Thus, as represented by a brokenarrow Y, cooling water is commonly guided to the annular gap β and theback pressure space α.

The pressure of water guided to the annular gap β is applied to the seatface 2 a. As a result, as water pressure increases, a force to separatethe valve seat 2 from the ball valve 1 becomes larger.

A circulatory system of engine cooling water in a vehicle adopts awell-known sealed pressurized cooling method. In the method, when theengine is driven to increase water temperature, water pressure rises to,for example, a valve opening pressure of a radiator cap. That is, thepressure of cooling water supplied from the engine to the inlet of thevalve device varies.

As described above, the valve device in the embodiment is provided withthe back pressure space α and the annular gap β, and intentionallyguides water pressure to the seat face 2 a and the seat opposite face ofthe valve seat 2 at closing.

This can offset the force applied from the seat opposite face to thevalve seat 2 and the force applied from the seat face 2 a to the valveseat 2 each other.

Thus, the force to press the valve seat 2 onto the ball valve 1 can bebrought closer to only the biasing force of the spring 6, and even whenwater pressure increases or decreases, a change in the force to pressthe valve seat 2 onto the ball valve 1 can be suppressed. This can keepa sliding resistance between the ball valve 1 and the valve seat 2substantially constant.

Specifically, since the driving force to rotate the ball valve 1 can besuppressed, the electrical actuator that rotates the ball valve 1 can bereduced in size. Sliding wear can be suppressed to increase long-termreliability of the valve device.

In the valve device, the curvature radius of the ball face 1 a is madesmaller than the curvature radius of the seat face 2 a, and thecurvature difference between the ball face 1 a and the seat face 2 aforms the contact ring A that contacts the ball face 1 a at the radiallyinner end of the seat face 2 a. For this reason, it is no need toprocess the contact ring A into an annular rib, reducing costs forforming the annular gap β.

The valve device applies the pressure of water guided to the backpressure space α to the ring plate 8 b extended at one end of the sleeve8, acting the pressure onto the seat opposite face via the ring plate 8b.

With the configuration, cooling water can be guided from the outercircumferential side of the back pressure space α to the back pressurespace α, as well as from the outer circumferential side of the annulargap β to the annular space. Specifically, cooling water can be directlyguided from the space that houses the ball valve 1 in the housing 3 toboth the back pressure space α and the annular gap β.

In the valve device, a pressure-receiving projection area in which waterpressure is applied to the seat opposite face from the back pressurespace α is the substantially same as a pressure-receiving projectionarea in which water pressure is applied to the seat face 2 a from theannular gap β.

Accordingly, a difference between water pressure that acts on the seatopposite face of the valve seat 2 and water pressure that acts on theseat face 2 a can be made closer to zero, bringing a force applied tothe valve seat 2 by water pressure to almost zero.

Thus, the sliding resistance between the ball valve 1 and the valve seat2 can be kept more constant, thereby suppressing an increase in thedriving force for the ball valve 1 due to an increase in water pressuremore reliably.

Fourth Embodiment

A fourth embodiment will be described with reference to FIGS. 6 and 7.The housing 3 of the valve device includes three cooling water outlets.The three cooling water outlets are distinguished one another as firstto third outlets 11 to 13. The first outlet 11 is a cooling water outletthat guides cooling water passing through the engine to a radiator. Thesecond outlet 12 is a cooling water outlet that guides cooling waterpassing through the engine to an air-conditioning heater core. The thirdoutlet 13 is a cooling water outlet that guides cooling water passingthrough the engine to an oil cooler or an oil warmer of a transmission.

Configuration for opening or closing the first to third outlets 11 to 13is the same as the valve device disclosed in the first embodiment, andincludes:

-   -   a housing 3;    -   a shaft 14 rotatably supported with respect to the housing 3;    -   an electrical actuator 15 that rotates the shaft 14;    -   a ball valve 1 that rotates integrally with the shaft 14; and    -   a ring-like valve seat 2 pressed onto the ball valve 1.

As an example, the housing 3 is directly assembled to the engine, andthe engine attachment face has an inlet 16 that guides cooling water tothe inside of the housing 3. Specifically, a valve chamber 17 thatcommunicates with the inlet 16 and houses the ball valve 1 is providedin the housing 3, and a space between the valve chamber 17 and the ballvalve 1 is filled with cooling water supplied from the inlet 16.

The housing 3 has a first outlet passage 11 a that guides cooling waterfrom the valve chamber 17 to the first outlet 11, a second outletpassage 12 a that guides cooling water from the valve chamber 17 to thesecond outlet 12, and a third outlet passage (not illustrated) thatguides cooling water from the valve chamber 17 to the third outlet 13.

Although not limited, in the housing 3, the first outlet passage 11 a isfarther from the inlet 16, and the second outlet passage 12 a and thethird outlet passage are closer to the inlet 16.

The first outlet passage 11 a is a flow path in which cooling waterflows from the engine toward the radiator. For this reason, a diameterof the flow path of the first outlet passage 11 a is larger than that ofthe second outlet passage 12 a and the third outlet passage so as toflow cooling water at a high flow rate.

The shaft 14 is disposed so as to pass the center of the valve chamber17. One end of the shaft 14 is rotatably supported via a ball bearing 18assembled to the housing 3, and the other end of the shaft 14 isrotatably supported via a bearing plate 19 attached to the inlet 16. Thebearing plate 19 has an opening that allows cooling water to pass.

The electrical actuator 15 has well-known configuration. For example,the electrical actuator 15 is configured as an electric motor thatconverts electric power into a rotational torque, a decelerationmechanism that decelerates rotation of the electric motor to increase adriving torque of the shaft 14, and a non-contact rotational anglesensor that detects rotational angle of the shaft 14.

The ball valve 1 is rotated by the electrical actuator 15 via the shaft14. The ball valve 1 is substantially cup-shaped. Describing the flowdirection of cooling water, cooling water supplied from the inlet 16 isfed to the inner side of the ball valve 1 through the cup opening. Then,the ball valve 1 is rotated and the valve opening 1 b and the seatopening 2 b overlap each other, cooling water flows through theoverlapping portion. That is, the valve device in the embodiment rotatesthe ball valve 1 to change the degree of communication between the inlet16 and the first to third outlets 13.

Here, the center of a flow path that guides fluid from the outside ofthe ball valve 1 into the cup is defined as an inlet axis jα. The centerof a flow path that discharges fluid from the cup of the ball valve 1 tothe first outlet passage 11 a is defined as an outlet axis jβ.

In the embodiment, one of the inlet axis jα and the outlet axis jβ isprovided in the same direction as the rotational axis of the ball valve1, and the outlet axis jβ is provided at an obtuse angle relative to theinlet axis jα.

That is, the ball valve 1 has the cup opening provided in the samedirection as the rotational axis of the ball valve 1. The rotationalaxis of the ball valve 1 is provided at an obtuse angle relative to theoutlet axis jβ or the inlet axis jα.

This will be specifically described below. The cup opening, which servesas an inlet for fluid in the ball valve 1, is opened in the rotationalaxis direction. The inlet 16 formed in the housing 3 is also provided inthe rotational axis direction of the ball valve 1. In this manner, theinlet axis jα is the same direction as the rotational axis of the ballvalve 1.

In the embodiment, among the first outlet passage 11 a, the secondoutlet passage 12 a, and the third outlet passage not illustrated, theoutlet passage having the largest diameter of the flow path is the firstoutlet passage 11 a that can guide a large quantity of cooling water tothe radiator.

In the embodiment, the outlet axis jβ that guides cooling water to thefirst outlet passage 11 a having the largest flow path diameter isprovided at an obtuse angle (for example, 100° to 150°) relative to therotational axis of the ball valve 1.

The center of a flow path that guides fluid from the inner side of theball valve 1 to the second outlet passage 12 a via the valve opening 1 bis defined as a second outlet axis jγ. Although not limited, the secondoutlet axis jγ is formed at right angle relative to the rotational axis.

In the valve device, the cup opening that guides cooling water to theinside of the ball valve 1 is opened in the rotational axis direction ofthe ball valve 1. The rotational axis of the ball valve 1 is provided atan obtuse angle relative to the outlet axis jβ. That is, the outlet axisjβ is provided at an obtuse angle relative to the inlet axis jα.

Accordingly, a bending angle of cooling water that travels from theinlet 16 to the first outlet passage 11 a through the inside of the ballvalve 1 can be made gentle, reducing a pressure loss of cooling waterthat travels from the ball valve 1 toward the first outlet passage 11 a.

As described above, since the bending angle from the inlet 16 to thefirst outlet passage 11 a can be made gentle to reduce the pressureloss, the diameter of the first outlet passage 11 a and the diameter ofthe valve opening 1 b that guides cooling water to the first outletpassage 11 a can be reduced to miniaturize the valve device. That is,the valve device can reduce the pressure loss while being downsized.

The portion of the ball valve 1, which slides on the valve seat 2, has aconvex spherical shape and thus, the angle of each of the outlet axis jβand the second outlet axis jγ with respect to the rotational axis can beflexibly set.

For this reason, when one or both of the first outlet passage 11 a andthe second outlet passage 12 a has a limitation in mounting, theorientation of the first outlet passage 11 a and the second outletpassage 12 a can be changed so as not to become obstacles, improving themounting feature of the valve device to vehicles.

Among the first outlet passage 11 a, the second outlet passage 12 a, andthe third outlet passage not illustrated, the outlet passage having thelargest diameter of the flow path is the first outlet passage 11 a thatcan guide a large quantity of cooling water to the radiator.

Thus, in the embodiment, the outlet axis jβ of the first outlet passage11 a having a large flow path diameter is provided at an obtuse anglerelative to the inlet axis jα.

Accordingly, the bending angle of cooling water travelling from theinlet 16 to the first outlet passage 11 a that guides the cooling waterto the radiator can be made gentle. For this reason, the pressure lossof a large quantity of cooling water flowing from the engine toward theradiator can be readily suppressed.

Fifth Embodiment

A fifth embodiment will be described below with reference to FIG. 8 toFIG. 11. An engine cooler has a cooling water circuit that forcedlycirculates cooling water in an engine 21 to cool the engine 21. Thecooling water circuit has a first circuit that circulates cooling waterin the engine 21, a radiator 22, and a water pump 23 in this order, asecond circuit that circulates cooling water in the engine 21, a heatercore 24 of an air conditioner, and the water pump 23 in this order, anda third circuit that circulates cooling water in the engine 21, a device25, and the water pump 23 in this order.

Cooling water is, for example, LLC containing ethylene glycol. Theheater core 24 exchanges heat between cooling water flowing out of theengine 21 and air, to heat the air. The device 25 is, for example, anoil cooler or a turbo charger, and requires heat-exchange with coolingwater flowing out of the engine 21.

The engine 21 includes a cylinder head 26 and a cylinder block 27, andthe cylinder head 26 and the cylinder block 27 are provided with a waterjacket 28 that circulates cooling water.

A valve device 29 that controls the flow rate of cooling water isdisposed in the cooling water circuit. The valve device 29 is disposedat an outlet of the water jacket 28. The valve device 29 is athree-direction flow rate adjustment valve that adjusts the flow rate ofcooling water in the first circuit, the second circuit, and the thirdcircuit. The valve device 29 may be multi-direction flow rate adjustmentvalve that adjusts the flow rate in three or more directions.

The cooling water circuit is filled with cooling water by performing avacuuming process of vacuuming the entire circuit and then, injectingcooling water using the negative pressure. The first circuit has a flowpath that bypasses the radiator 22, and a reserve tank 22 a provided inthe middle of the flow path is vacuumed to inject cooling water.

The valve device 29 includes:

-   -   a housing 3 that houses the ball valve 1;    -   a shaft 14 that penetrates the housing 3, and rotates integrally        with the ball valve 1;    -   a seal member 31 that seals a portion between the housing 3 and        the shaft 14; and    -   a labyrinth 32 that attenuates kinetic energy of fluid going        toward the seal member 31 in the housing 3.

The housing 3 has a shaft reception hole 33 that penetrates the housing3 and receives the shaft 14. The shaft reception hole 33 penetrates thehousing 3, and has an opening communicating with the valve chamber 17.Hereinafter, the opening of the shaft reception hole 33, whichcommunicates with the valve chamber 17, is referred to as a shaftreception opening 33 a.

The axial direction of the shaft reception hole 33 is defined as a valveshaft direction. A side near the valve chamber 17 is defined as one sidein the valve shaft direction, and its opposite side is defined as theother side in the valve shaft direction.

The other end of the shaft reception hole 33 in the valve shaftdirection is opposed to an actuator chamber 35 formed between a cover 34attached to the housing 3 and the housing 3. The actuator chamber 35 isa space that houses the gear 36 constituting the deceleration mechanismand so on.

A portion of the shaft 14, which protrudes toward the other side in thevalve shaft direction of the shaft reception hole 33, is fixed to thegear 36 in the actuator chamber 35.

In the embodiment, the cup opening of the ball valve 1 is provided asopposed to the shaft reception opening 33 a in the valve shaft directionacross the ball valve 1.

The shaft 14 is inserted into the shaft reception hole 33, and isrotatably supported by the ball bearing 18 interposed between thehousing 3 and the shaft 14.

The ball valve 1 is housed in the valve chamber 17 as well as held inthe shaft 14, and is rotated with rotation of the shaft 14 to change theflow rate of cooling water flowing from the cup opening to each valveopening 1 b.

The ball valve 1 is fixed to the shaft 14 by inserting the shaft 14 intoa shaft hole 14 a in the ball valve 1 and fixing the state.

Thus, the opening of the shaft hole 14 a is opposed to the shaftreception opening 33 a in the valve shaft direction.

The seal member 31 is disposed between the inner circumferential face ofthe shaft reception hole 33 and the outer circumferential face of theshaft 14 to seal space on the opposite side to the valve chamber 17against the valve chamber 17 in a liquid-tight manner. The seal member31 functions to prevent leakage of cooling water from the valve chamber17 to the actuator chamber 35.

The seal member 31 is a general shaft seal component having an annularmetal portion 31 a and an annular rubber portion 31 b using the metalportion 31 a as a core. The rubber portion 31 b is made of a rubbermaterial, and has a seal lip that elastically contacts the outercircumferential face of the shaft 14.

The seal lip has a first lip 44 a that protrudes toward the one side inthe valve shaft direction, a second lip 44 b that protrudes toward theother side in the valve shaft direction, and a third lip 44 c providedbetween the first lip 44 a and the second lip 44 b. Only the first lip44 a may be provided.

The shaft reception hole 33 is enlarged in the inner diameter from theother side in the valve shaft direction toward the one side in the valveshaft direction in two stages. The first stage is referred to as amiddle-diameter rear portion 33 b, and the second stage is referred toas a large-diameter rear portion 33 c. The seal member 31 is disposed atthe large-diameter rear portion 33 c. The face of the seal member 31 atthe other side in the valve shaft direction abuts a stepped face betweenthe middle-diameter rear portion 33 b and the large-diameter rearportion 33 c. An inner space of the middle-diameter rear portion 33 bslightly communicates with the actuator chamber 35 through a clearanceof the ball bearing 18 and however, the seal member 31 prevents leakageof cooling water from the valve chamber 17 to the actuator chamber 35.

The labyrinth 32 is provided in a gap extending from the valve chamber17 to the seal member 31 via the shaft reception opening 33 a toattenuate kinetic energy of the cooling water travelling toward the sealmember 31.

The labyrinth 32 is formed using a tubular portion 50 that protrudesfrom an opening edge of the shaft reception opening 33 a toward thevalve chamber 17 and surrounds the outer circumferential face of theshaft 14 with a clearance C1, and a peripheral wall 51 of the ball valve1 that is radially opposed to the outer circumferential face 50 a of thetubular portion 50 with a clearance C2.

The housing 3 has the tubular portion 50 that protrudes from the openingedge of the shaft reception opening 33 a toward the valve chamber 17.The tubular portion 50 protrudes from the inner wall face of the valvechamber 17 toward the one side in the valve shaft direction, and isshaped like a tube that is coaxial with the shaft 14. Specifically, theone end of the large-diameter rear portion 33 c in the valve shaftdirection defines the shaft reception opening 33 a. The innercircumferential face 50 b of the tubular portion 50 is flush with theinner circumferential face of the large-diameter rear portion 33 c.

The ball valve 1 has a recess 53 formed at a site opposed to the shaftreception opening 33 a. The recess 53 has the peripheral wall 51radially opposed to the outer circumferential face of the shaft 14, anda flat face 54 that is perpendicular to the shaft 14 and is opposed tothe end face of the tubular portion 50.

The tubular portion 50 protrudes into the recess 53. That is, thetubular portion 50 and the recess 53 overlap each other in the valveshaft direction, and the tubular portion 50 and the peripheral wall 51overlap each other in the radial direction.

Thus, the flow of cooling water travelling from the valve chamber 17toward the seal member 31 must pass through the clearance C2 between theperipheral wall 51 and the outer circumferential face 50 a of thetubular portion 50 and a clearance C3 between the flat face 54 and theone-side face of the tubular portion 50 in the valve shaft direction.That is, the flow path from the valve chamber 17 to the seal member 31through the shaft reception opening 33 a meanders to attenuate kineticenergy of cooling water travelling toward the seal member 31.

The tubular portion 50 has a stopper 56 that locks the ball valve 1 inthe rotating direction and limits the rotational range of the ball valve1 with respect to the housing 3. The stopper 56 is provided as aprotruding portion that protrudes from the outer circumferential face 50a of the tubular portion 50 toward the outer circumference.

The stopper 56 can contact the protruding portion 57 provided on theperipheral wall 51 so as to protrude inward, in the rotating direction.Thus, the ball valve 1 stops its rotation at the position where thestopper 56 contacts the protruding portion 57.

The valve device 29 includes a labyrinth 32 that attenuates kineticenergy of cooling water travelling from the valve chamber 17 toward theseal member 31 via the shaft reception opening 33 a.

The labyrinth 32 attenuates kinetic energy of cooling water travellingfrom the valve chamber 17 toward the seal member 31 via the shaftreception opening 33 a, reducing a shock caused when cooling water hitsagainst the seal member 31 to prevent peeling of the first lip 44 a.

Therefore, leakage of cooling water from the valve chamber 17 throughthe shaft reception hole 33 can be reliably prevented.

Specifically, by vacuuming the cooling water circuit and then, injectingcooling water, the valve device 29 is filled with cooling water. In thismanner, in the process of injecting cooling water, cooling waterforcibly flows into the valve chamber 17. For this reason, withconventional configuration, a first lip 44 a may be peeled by a largeshock of the water pressure. On the contrary, in the embodiment, thelabyrinth 32 can present peeling of the first lip 44 a.

The labyrinth 32 is formed by the tubular portion 50 that surrounds theouter periphery of the shaft 14 with the clearance C1, and theperipheral wall 51 radially opposed to the outer circumferential face 50a of the tubular portion 50 with the clearance C2. This can readily formthe labyrinth 32.

The tubular portion 50 has the stopper 56 that limits the rotationalrange of the ball valve 1.

Generally, a stopper that limits the rotational range of the ball valve1 is provided in the housing 3 so as to lock a gear 36. However, in thiscase, when the fixation site of the shaft 14 and the ball valve 1 isbroken, only the shaft 14 is limited in its rotation, and the ball valve1 goes into s freewheeling condition.

On the contrary, in the embodiment, since the stopper 56 directly stopsrotation of the ball valve 1, even when the fixation site of the shaft14 and the ball valve 1 is broken, rotation of the ball valve 1 can bestopped.

Modifications in the Fifth Embodiment

The labyrinth 32 is not limited to the above embodiment. For example, asillustrated in FIG. 12, in addition to the peripheral wall 51, aperipheral wall 59 radially opposed to an inner circumferential face 50b of the tubular portion 50 with a clearance C4 may be provided in theball valve 1.

Thus, an inner circumferential side face of a peripheral groove 60 formsthe peripheral wall 59 radially opposed to the inner circumferentialface 50 b of the tubular portion 50 with the clearance C4, and an outercircumferential side face of the peripheral groove 60 forms theperipheral wall 51 radially opposed to the outer circumferential face 50a of the tubular portion 50 with the clearance C2.

The labyrinth 32 illustrated in FIG. 12 also can cause the flow pathextending from the valve chamber 17 to the seal member 31 via the shaftreception opening 33 a to meander, thereby attenuating kinetic energy ofcooling water travelling toward the seal member 31.

As illustrated in FIG. 12, the inner diameter of the tubular portion 50may be larger than the diameter of the shaft reception opening 33 a tosurround the shaft reception opening 33 a.

In a modification of the configuration illustrated in FIG. 12, theperipheral wall 51 may be omitted. That is, with the configuration, theball valve 1 has the peripheral wall 59 radially opposed to the innercircumferential face 50 b of the tubular portion 50 with the clearanceC4 to form the labyrinth 32.

Alternatively, as illustrated in FIG. 13, the ball valve 1 may have atubular portion 62 inserted into the shaft reception hole 33 to form thelabyrinth 32.

In this case, the tubular portion 62 may be disposed such that the firstlip 44 a is located on the inner side of the tubular portion 62. Aflange 62 a that extends outward may be provided on the other end of thetubular portion 62 in the valve shaft direction, and an inner flange 63that protrudes inward may be provided on the inner circumferential faceof the shaft reception hole 33, which is closer to the one side in thevalve shaft direction than the flange 62 a.

With the configuration illustrated in FIG. 13, the seal member 31 isassembled by being passed on the inner side of the inner flange 63 whilebeing compressively deformed. Alternatively, after assembling of theseal member 31, the inner flange 63 as a separate member may beassembled.

The labyrinth 32 illustrated in FIG. 13 also can cause the flow pathextending from the valve chamber 17 to the seal member 31 via the shaftreception opening 33 a to meander, thereby attenuating kinetic energy ofcooling water travelling toward the seal member 31.

In the embodiments, the ball valve 1 is cup-shaped. However, the ballvalve 1 may have any shape as long as the face that slides on the valveseat 2 has a convex spherical shape.

In the embodiments, the ball valve 1 and the valve seat 2 may be made ofresin. However, the material for the ball valve 1 and the valve seat 2is not limited.

In the embodiments, the curvature radius R1 of the ball face 1 a issmaller than the curvature radius R2 of the seat face 2 a. However, thecurvature radius R1 of the ball face 1 a may be equal to the curvatureradius R2 of the seat face 2 a.

In the embodiments, the curvature difference between the ball face 1 aand the seat face 2 a forms the contact ring A. However, the contactring A may be formed in any suitable manner. For example, when thecurvatures of the ball face 1 a and the seat face 2 a are same as eachother, the contact ring A may be provided by forming an annular rib onthe radially inner side of the seat face 2 a.

In the embodiments, the sleeve 8 is fixed to the valve seat 2 bypress-fitting. However, the sleeve 8 may be fixed to the valve seat 2using an adhesive, for example.

In the embodiments, fluid flows from the inner side to the outer side ofthe ball valve 1 at opening. However, fluid may flow in the oppositedirection.

In the embodiments, the electrical actuator 15 rotates the ball valve 1.However, the ball valve 1 may be driven by any means.

In the embodiments, the compression coil spring is used as an example ofthe spring 6. However, the ball valve 1 and the valve seat 2 may becompressed by any means.

In the embodiments, the present disclosure is applied to the valvedevice that controls engine cooling water. However, the presentdisclosure may be applied to a valve device that controls cooling waterin a vehicle including no engine.

In the embodiments, the present disclosure is applied to the valvedevice that controls liquid. However, fluid is not limited to liquid,and the present disclosure may be applied to a valve device thatcontrols gas.

The above-described plurality of the embodiments may be combined.

What is claimed is:
 1. A valve device comprising: a housing having aninlet that lets in cooling water from an internal combustion engine andan outlet that lets out the cooling water; a valve being rotated about arotational axis inside the housing, the cooling water being suppliedinto the valve from the inlet; and a valve seat having a ring shape tobe in contact with a seat face of the valve, the valve seat beingdisposed in a flow path guiding the cooling water from the valve to theoutlet, wherein a center of the flow path guiding the cooling water fromthe valve to the outlet is defined as an outlet axis, and a center of aflow path guiding the cooling water from the inlet into the valve isdefined as an inlet axis, the rotational axis extends in a direction ofthe inlet axis, and the outlet axis is provided at an obtuse anglerelative to the inlet axis, the outlet is one of a plurality of outletsin the housing, an open area of the inlet is larger than an open area ofa first outlet, the open area of the inlet is larger than an open areaof a second outlet, the open area of the first outlet is larger than theopen area of the second outlet, a center of a flow path guiding thecooling water from the valve to the first outlet is defined as a firstoutlet axis, a center of a flow path guiding the cooling water from thevalve to the second outlet is defined as a second outlet axis, and anangle defined between the inlet axis and the first outlet axis is largerthan an angle defined between the inlet axis and the second outlet axis.2. The valve device according to claim 1, wherein the valve has a firstinner wall part having a cylindrical shape extending in a direction ofthe rotational axis, and a second inner wall part that is curved andsmoothly connected with the first inner wall part, wherein the secondinner wall part extends in a direction to narrow the first inner wallpart.
 3. The valve device according to claim 1, wherein the valve seatis biased toward the seat face.
 4. The valve device according to claim1, wherein the outlet is one of a plurality of outlets defined in thehousing, and the valve seat is provided to each of the plurality ofoutlets, and a valve opening defined in the valve is an ellipse holeextending in a rotating direction of the valve.
 5. The valve deviceaccording to claim 1, wherein the valve is a ball valve having a ballface shaped in a convex spherical surface.
 6. A valve device comprising:a housing having an inlet that lets in cooling water from an internalcombustion engine and an outlet that lets out the cooling water; a valvebeing rotated about a rotational axis inside the housing, the coolingwater being supplied into the valve from the inlet; and a valve seathaving a ring shape to be in contact with a seat face of the valve, thevalve seat being disposed in a flow path guiding the cooling water fromthe inlet into the valve, wherein a center of the flow path guiding thecooling water from the inlet into the valve is defined as an inlet axis,and a center of a flow path guiding the cooling water from the valve tothe outlet is defined as an outlet axis, the rotational axis extends ina direction of the outlet axis, and the outlet axis is provided at anobtuse angle relative to the inlet axis, the inlet is one of a pluralityof inlets in the housing, an open area of the outlet is larger than anopen area of a first inlet, the open area of the outlet is larger thanan open area of a second inlet, the open area of the first inlet islarger than the open area of the second inlet, a center of a flow pathguiding the cooling water from the first inlet to the valve is definedas a first inlet axis, a center of a flow path Guiding the cooling waterfrom the second inlet to the valve is defined as a second inlet axis,and an angle defined between the outlet axis and the first inlet axis islarger than an angle defined between the outlet axis and the secondinlet axis.
 7. The valve device according to claim 6, wherein the valvehas an inner wall surface parallel with the seat face.
 8. The valvedevice according to claim 6, wherein the valve is a ball valve having aball face shaped in a convex spherical surface.
 9. A valve devicecomprising: a housing having an inlet that lets in cooling water from aninternal combustion engine and an outlet that lets out the coolingwater; a valve being rotated inside the housing; and a valve seat havinga seat face, the seat face being pressed onto the seat face of thevalve, wherein the valve is rotated to open by communicating a valveopening defined in the valve and a seat opening defined in the valveseat with each other, a center of a flow path guiding the cooling waterfrom the inlet into the valve is defined as an inlet axis, and a centerof a flow path guiding the cooling water from the valve to the outlet isdefined as an outlet axis, the outlet axis is provided at an obtuseangle relative to the inlet axis, the outlet is one of a plurality ofoutlets in the housing, an open area of the inlet is larger than an openarea of a first outlet, the open area of the inlet is larger than anopen area of a second outlet, the open area of the first outlet islarger than the open area of the second outlet, a center of a flow pathguiding the cooling water from the valve to the first outlet is definedas a first outlet axis, a center of a flow path guiding the coolingwater from the valve to the second outlet is defined as a second outletaxis, and an angle defined between the inlet axis and the first outletaxis is larger than an angle defined between the inlet axis and thesecond outlet axis.
 10. The valve device according to claim 9, whereinthe valve is a ball valve having a ball face shaped in a convexspherical surface, the ball valve has a cup shape, and the seat face isshaped in a concave spherical surface, and is pressed onto the ballface.